Essentially, the Vahi-Ra was once a regular Rahi beast until the Toa Vahi decided it needed a pet, and chose this. Double the size of the regular species and control of the power of sonics makes this Rahi a match even for the Toa.

Quoting Yuri Fassio
Amazing! How you managed to put all this stuff together greatly baffles me... The legs and tail structure is... well, I don't know what its, choose a word yourself. It reminds me of Breanne Sledge's awesome structures, take a look here http://www.mocpages.com/home.php/16168

Thank you! :) I know, it baffles me too! Would baffling suffice? :P. My models like this are more a case of putting pieces together randomly and hoping they work, and sticking more on top when they do until I've used most of them up, and trying to remember what does and doesnt work on the next one. But it seems to work! I can try put together a photo step-by-step guide for my next one if you like. It won't be quite as prefessional as Breanne's but I can always dream!

Amazing! How you managed to put all this stuff together greatly baffles me... The legs and tail structure is... well, I don't know what its, choose a word yourself. It reminds me of Breanne Sledge's awesome structures, take a look here http://www.mocpages.com/home.php/16168